Got chased by a dog that had gotten loose from the fence of the used car lot it was guarding. That was probably the most horrifying. It was at the end of a long hill, too! Also ran into dogs on an overnighter, but was some 60 plus miles into the trip. Once it was two dogs and I was going up a hill and dead tired. They could have bitten me if they wanted to, but they were just doing the dog thing. I even had a chat and let them know I'd leave them alone if they would do the same.
That said, the next time I go out on a tour, especially if I'm by myself, I plan on carrying some pepper spray. If you are in the US, I would recommend a
foam based spray like this to avoid any blowback. The last thing you want to do is inhale a big burst of pepper spray while trying to escape an angry dog.